The present invention relates to a stabilizing and isolation system for mounting an operator cab on a vehicle frame, and more particularly, the invention relates to such a system permitting controlled vertical motion of the cab relative to the frame while restraining relative rolling and pitching motion of the cab.
Heretofore, most operators' cabs in construction vehicles, such as road planers, graders, and the like, have been mounted on the chassis or frame of the vehicle with resilient cushioning means interposed therebetween functioning as a suspension system. Many prior art suspension systems have simply used elastomeric isolators having high spring rate (made from relatively stiff material) to provide a stable suspension. However, since the isolators have been formed from relatively stiff material, the degree of isolation of the cab from the frame has been relatively reduced. By reducing the isolation of the cab from the frame, vibrations and impacts caused by vibrating bodies such as the engine, pump, transmission, cutting drum, and torque converter used on the vehicle or transmitted from the exterior of the vehicle, are applied to the operator's cab thereby raising the noise level in the cab and concomitantly diminishing the comfort level of the operator.
The present invention utilizes elastomeric isolators made from relatively softer material thus providing a relatively low spring rate to provide a "softer" ride for the operator within the cab. However, since isolators made from relatively soft material provide a relatively unstable suspension system, the present invention also includes means to stabilize the cab relative to the frame by restraining pitching and rolling motion of the cab. By using the elastomeric isolators formed from relatively softer material, the cab is more effectively isolated from the frame.
By utilizing the suspension and isolation system of the present invention, numerous advantages are obtained. Such advantages include reduced operator fatigue and increased operator productivity. By isolating the cab relative to the frame, the expected life of the cab related hardware will be prolonged. There will be less need to provide specialized shock mounting for the instrumentation and controls located in the cab. The need to provide a special suspension on the operator's seat will either be reduced or entirely eliminated. By reducing or eliminating the suspension in the operator's seat, only minimum, if any, relative motion between the operator and the controls located in the cab will occur. By minimizing the relative motion between the operator and his controls, there will be significant improvement in safety by providing for more precise control. Further, operator fatigue will be reduced since it is easier to focus the eye on, or grasp and manipulate, a stationary target. Furthermore, by using a relatively "soft" suspension system, the need to isolate the engine from the vehicle frame is either reduced or eliminated.